Electrical plug



' Dec. 17, 1935.

J. G. ALLEN, JR

ELECTRICAL PLUG Filed April 9, i954- Patented Dec. 17, 1935 UNITEDSTATES PATENT OFFlCE 4 Claims.

This invention relates to new and useful improvements in electricalplugs.

One object of the invention is to provide an improved plug whicheliminates the usual metal fastenings for the lead wires.

Another object of the invention is to provide an improved plug which iseasily and quickly assembled or dissembled, whereby the connection ofthe lead wires thereto is readily accomplished.

A further object of the invention is to provide an electrical plug whichis so arranged as to provide a constant positive contact of the leadwires with the contact prongs of said plug.

Still another object of the invention is to provide an electrical plugwhich is constructed in two pieces, whereby manufacture is simplifiedand also a more efiicientplug is provided.

A particular object of the invention is to' provide'an improvedelectrical plug which has the lead wires secured thereto by bending thesame around projections within the plug and is arranged in such a waythat the exposed ends of the wires frictionally engage the contactprongs of the plug, thereby assuring a positive contact.

A construction designed to carry out the invention will be hereinafterdescribed, together with other features of the invention.

The invention will be more readily understood from a reading of thefollowing specification and by reference to the accompanying drawing, inwhich an example of the invention is shown, and wherein:

Figure l is an elevation of a plug, constructed in accordance with theinvention.

Figure 2 is a vertical sectional view of the same.

Figure 3 is a vertical sectional view, taken at right anglesto Figure 2.

Figure 4 is a view similar to Figure 2 showing the block partly removedfrom the shell of the plug.

Figure 5 is a view similar to Figure 4, and taken at right anglesthereto.

Figure 6 is a horizontal cross sectional view, taken on the line 6-6 ofFigure 4,

Figure 7 is an isometric view of the block, and

Figure 8 is an elevation of a modified form of contact prongs.

In the drawing, the numeral It designates the concave-convex shell of anelectrical plug which is generally circular in cross section. The shellis constructed of suitable insulating material and has a dependingannular fiange H at its lower end. A hollow tubular fiared extension I2is provided at the upper end of the shell and said extension, shell andflange are all made integral, being of the same material andconstituting the body of the plug.

Within the shell of the plug, a pair of diametrically opposite bosses i3are positioned. 5 These bosses are of insulating material and arepreferably made integral with the shell l0. Elongated fiat contactprongs I4 are provided with brackets I4 secured to the bosses l3 byscrews I5 and extend outside the body a sub- 10 stantial distance fromthe flange H. Although I have shown the prongs secured by the screwsl5,.it is obvious that any suitable means may be employed to'fasten saidprongs to the bosses.

Further, prongs M (Fig. 8) could be substituted for the prongs I4. Eachprong l4 comprises a flat piece of metal bent upon itself as shown toform a prong and fastening bracket of a single piece of metal.

As is .well known, the contact prongs conduct 20 the electrical currentto or from the lead wires A and B which engage said prongs. The usualmethod is to secure the exposed ends of the Wires to the screws, therebymaking electrical connection with the prongs. The connection 25 must bemade with tools, and due to the necessary smallness of the plug, it isdifficult and tedious to properly secure the wires to said screws. Theconnections when finally made are poor and insecure, because any strainon the 30 wires A and B is taken by the outer fastened ends of thewires, resulting in loosened contacts short circuiting and causing fuseblowouts, and other troubles.

For electrically connecting the lead wires A 35 and B to the contactprongs I4 to overcome the above disadvantages, a square block I6 isprovided. This block is positioned centrally of a circular plate or diskI? which is made integral with or fastened to the lower end of theblock. The block 40 and disk are constructed of any suitable insulatingmaterial, such as hard rubber, rubber compound, and the like. The blockis arranged to be inserted into the shell Ii) of the plug, two of thesides [9 of the block lying contiguous to 45 the inner fiat sides .ofthe prongs I4 and the periphery of the disk engaging the inner rim ofthe flange I I (Figures 2 and 3). Slots l6 are provided in the diskadjacent the sides 19 of the block and the prongs I4 pass downwardly 50through these slots when the block is in position within the shell In.It is noted that the disk has a close fit within the flange ll.

Both the lead wires A and-B are fastenedin I the block in the same wayand it is believed that 55 a description of one will suflice. Forsecuring the lead wire A to the block, said block is provided near itsupper end with a diagonal duct I8 which extends horizontally throughsaid block. One end of the duct terminates at one of the sides I9 of theblock which lie contiguous to one of the prongs l4 when the block is inposition within the shell H), the other end terminating at theadjacentside 20 thereof. A flange 2| extends outwardly from the side 20near its lower end and this flange extends substantially the width ofsaid side being made integral therewith. Each end of the flange isprovided with a notch 22 and at the upper central portion of the side20, a small recess 23 is formed.

In securing the wire A in the block, said wire is passed downwardlythrough the extension l2 and through the shell of the plug. The block I6is not in position within said body at this time, being free therefrom.The wire A is laid in the recess 23 and passed under and around theflange 2| (Figure 7 engaging in the notches 22 to prevent itsdisengagement from the flange. The end of the wire is bent upwardly andis pushed into the duct |8 from the side 20, through the duct and outonto the side H). The end of the wire is then bent so as to lie alongthe flat side l9. It is pointed out that only that part of the wirelying along the side |9 is exposed, the remainder being suitably coveredwith insulation a. Due to the winding of the wire around the flange 2|,its engagement in the notches and duct and its bending, said wire isprevented from slipping, once it is in position.

A diagonal duct I8 is provided on the opposite side of the block l6 andanother flange 2| is formed on the opposite side 2E The wire 13 ispassed downwardly through the shell I of the plug, is wound around thecorresponding flange 2| and is pushed through, the second duct I8,having its outer end exposed and lying along the second side N! of theblock.

When the wires have been secured to the block, as above described, theblock is slid upwardly within the shell |0, theprongs M entering thespots I6, whereby the block passes upwardly between the prongs, theinner sides of said prongs engaging the exposed ends of the wires A andB which lie along the sides IQ of the block. The contact prongs areplaced sufliciently close to each other so that as the block slidesupwardly therebetween, said prongs will frictionally engage the ends ofthe wires A and B. This frictional contact not only serves to hold theblock securely within the shell, but also affords a perfect and positiveelectrical connection between the prongs and wires.

The wires A and B are secured in the block before the same is insertedinto the shell of the plug. This permits plenty of room in which to makea fastening and also eliminates the necessity of using tools with whichto secure the lead wire to said block. When the block is slid upwardlywithin the shell the wires A and B tightly engage the inner sides of theprongs l4 and frictionally hold said block within the shell. If anyundue strain is placed on the wires A and B, it will be seen that saidstrain will be taken by a goodly portion of the inner end of the wiresand not by a small portion of said Wires at their extreme inner ends, asis the case in the 'usual plug which depends on screw connections forits fastenings. It is obvious that the block is readily assembled anddisassembled to attach and detach the lead wires A and B to the block.By eliminating the usual screw contacts, the danger of the electricalconnection jarring loose, as well as the difficulty of making saidconnection, is eliminated.

The description which has been given recites more or less detail of aparticular embodiment of the invention, which is set forth as new anduseful; however, I desire it understood that the invention is notlimited to such exact details of construction, because it is manifestthat changes and modifications may be made, within the scope of theappended claims, without departing from the spirit of the invention. 15

What I claim and desire to secure by Letters Patent, is:

1. An electrical connection plug comprising, a hollow body, metalliccontact prongs mounted in said body and extending outward from the front0 face thereof, a block insertable in the body from the front facethereof between the prongs, and a disk at the lower end of the block andhaving slots through which said prongs project when the block and diskare inserted in said body, said block having means for engaging circuitwires and holding the ends thereof in frictional contact with saidprongs, said frictional contact maintaining the connection plugassembled.

2. An electrical connection plug comprising, a hollow body, metalliccontact prongs mounted in said body and extending outward from the frontface thereof, a block insertable in the body from the front face thereofbetween the prongs, and a disk at the lower end of the block connectedtherewith and having slots therein for receiving the contact prongs whenthe block is within the body, projections on said block for receivingcircuit wires and openings through the block through which bared ends ofsaid circuit wires extend, said block holding the ends of said wires infrictional contact with the prongs when the block is positioned withinthe body, said frictional contact maintaining the connection plugassembled.

3. An electrical connection plug comprising a hollow body, metalliccontact prongs mounted in said body and extending outward from the frontface thereof, and a block having openings therein for receiving circuitwires with the ends of said circuit wires passing through said openings,said block inserted in the body from the front face thereof between theprongs and serving to' hold the extending ends of said wires inelectrical contact with the prongs when the block is positionedtherebetween, said frictional contact maintaining the connection plugassembled.

4. An electrical connection plug comprising, a hollow body, metalliccontact prongs mounted in said body and extending outward from the front50 face thereof, a block having openings therein for receiving circuitwires with the ends of said circuit wires passing through said openings,said block inserted in the body from the front face thereof between theprongs, and projections on 5 the member around which said wires areengaged before passing through said openings to more securely fasten thesame to the block, said block serving to hold the extending ends of saidWires in electrical frictional contact with the prongs when the block ispositioned therebetween, said frictional contact maintaining the.connection plug assembled.

JOHN G. ALLEN, JR.

